Пусть u={1,2,3,4,5,6,7,8,9,10} a={1,2,3,4,5,6} b={2,4,6,8} c={1,3,5,7} d={4,5,7,8} вычислить : 1. (a∩d)∪(¬a∪¬b) - id637712720200117 от артбар 17.01.2020 00:12

Question

Алгебра: Пусть u={1,2,3,4,5,6,7,8,9,10} a={1,2,3,4,5,6} b={2,4,6,8} c={1,3,5,7} d={4,5,7,8} вычислить : 1. (a∩d)∪(¬a∪¬b) 2. a/(c/d)

артбар · Accepted Answer

cos²x +cos²y -sin²(x+y) = 2cosx  ;
(1+cos2x)/2 +(1+cos2y)/2 -(1-cos2(x+y))/2 = 2cosx  ;
1+cos2x +1+cos2y -1+cos2(x+y) = 4cosx  ;
(1+cos2(x+y) ) +(cos2x +cos2y )= 4cosx ;
2cos²(x+y) +2cos(x+y)cos(x-y) = 4cosx ;
2cos(x+y)( cos(x+y)+cos(x-y)) = 4cosx ;
2cos(x+y)*2 cosx*cosy = 4cosx ;
4cosx (cos(x+y)cosy -1) =0 ;
а) cosx =0 ;
x =π/2 +πk , k∈Z .
б) cos(x+y)cosy -1 =0 ⇔ cos(x+y)cosy=1 .
б₁) {cos(x+y) = -1 ; cosy= -1.
{ x+y =π+2πk ; y = π+2πn ⇒{x=2π(k -n) ; y = π+2πn .
б₂)  {cos(x+y) =1 ; cosy= 1 ;
{x+y =2πk ; y = 2πn ⇒{x=2π(k -n) ; y = 2πn .

Пусть u={1,2,3,4,5,6,7,8,9,10} a={1,2,3,4,5,6} b={2,4,6,8} c={1,3,5,7} d={4,5,7,8} вычислить : 1. (a∩d)∪(¬a∪¬b) 2. a/(c/d)

MOGZ ответил